Microlensing and the Structure of X-ray Emitting Regions in QSOs

摘要

We simulate microlensing of distant, multiply lensed quasars by stars in an intervening galaxy-lens. The calculations include the influence of the effect on the fluorescence Fe Kα lines. We use standard source models, involving accretion disks and a hot, diffuse component, which explain the presence of the lines as a result of radiation reprocessing in a cold disk. In all calculations we use cosmological and macro-lens parameters relevant to the source MG J0414+0534, a quasar where the iron line has been observed by Chandra. We investigate probability distribution for the line equivalent width of the microlensed source and find its dependence on the source model parameters. We show that the probability of a high strengthening of the line (as measured by the equivalent width) decreases sharply with the size of the emitting region. We apply the results of our simulations to the source MG J0414+0534. We find that the observed behavior of the source is not easy to reproduce with the help of the simplest disk and microlensing models. Of the models considered the best results are obtained with the disks around 10~7 M_⊙ black holes with inner edges at ≈10 gravitational radii.